The Isle of the Crocodile

This folktale tells of how the Creator of this world enlists the help of animals to hide from man three special objects within the world. To win the honor of helping to protect the objects, the Creator holds three separate contests with the winners, each taking a special object to an island made in their image, only later to be betrayed. What are these three special objects which must be protected? Where are they located? Who betrays the winners in the end?